UBC Theses and Dissertations
Motion compensation for airborne interferometric synthetic aperture radar Stevens, David Robert
Airborne SAR interferometry has the potential to provide topographic data with a precision of the order of one meter. However, to generate data accurate to this level it is essential to measure and compensate for the antenna baseline motion. Conventional motion compensation techniques and their errors are analyzed and extended to the two channel simultaneous imaging scenario of InSAR. An evaluation of the modelling is made using point target simulation and real motion and InSAR data. Phase compensation of both channels to the same reference track and compensation to two separate tracks are considered. The single track approach allows track segmentation to follow aircraft drifts without causing discontinuities in the differential phase, but is sensitive to range cell migration effects. The dual track approach is not sensitive to this but suffers from discontinuous differential phase at segmentation boundaries, which complicates the phase unwrapping process. A new formulation for each approach is presented that compensates for unknown terrain coupled with low frequency aircraft motion. In addition, a new approach that uses the dual track approach initially and then converts to a single reference track after compression is proposed. This realizes the benefits of both approaches with only a small increase in computation.
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